The present invention relates to an aseptic filling apparatus of the rotary type for use in filling a beverage or the like into containers in an aseptic state.
As disclosed in the publication of JP-A3-29703, conventional filling apparatus of the type mentioned include those comprising a turntable, a plurality of filling nozzles mounted on the peripheral portion of the turntable with their discharge outlets facing downward, a container support rotatable with the turntable and arranged for each of the filling nozzles for placing thereon the container to be filled, and an aseptic chamber provided for surrounding a path of transport of containers along with the turntable. An air discharge channel is provided between the turntable and the aseptic chamber and is opened to the atmosphere.
With the filling apparatus described, the aseptic chamber is held at a positive pressure with aseptic air during the steady-state filling operation, and the aseptic air is partly discharged to the atmosphere through the air discharge channel at all times.
There is no assurance that the air to be discharged through the air discharge channel will be uniform in flow rate or velocity over the entire circumference of the channel. This is attributable to the variations involved in the size of the air discharge channel in view of the working accuracy with which the turntable and the aseptic chamber are made. If variations occur in the rate of flow of the air to be discharged, the air will reversely flow into the channel, entailing the likelihood that the outside air will ingress into the aseptic chamber along with microorganisms. This impairs the aseptic nature of the aseptic chamber. The rotation of the turntable is also likely to produce turbulence in the vicinity of the air discharge channel, possibly causing the air to flow reversely into the channel.
To hold the aseptic chamber aseptic, on the other hand, there is a need to periodically sterilize the chamber with a sterilant, gas or the like, whereas the filling apparatus described permits the sterilant, gas or the like to be discharged to the atmosphere through the air discharge channel like the aseptic air. This results in the problem of causing contamination of the work environment.
An object of the present invention is to provide an aseptic filling apparatus of the rotary type wherein air can be prevented from reversely flowing into an air discharge channel and which is unlikely to give rise to the problem of causing contamination of the work environment.
The present invention provides an aseptic filling apparatus of the rotary type comprising a turntable, a plurality of filling nozzles mounted on a peripheral portion of the turntable and each having a discharge outlet directed downward, a container support rotatable with the turntable and arranged for each of the filling nozzles for placing thereon a container to be filled, and an aseptic chamber provided for surrounding a path of transport of containers along with the turntable, an air discharge channel being provided between the turntable and the aseptic chamber, the filling apparatus being characterized in that a channel control member is disposed so as to cover the air discharge channel, the channel control member being hermetically fixed to the aseptic chamber, a space between the turntable and the channel control member being sealed by seal means, a collection pipe being connected to the channel control member so as to communicate with the air discharge channel.
Thus, the aseptic filling apparatus of the invention has a channel control member so disposed as to cover the air discharge channel and hermetically fixed to the aseptic chamber, seal means sealing off a space between the turntable and the channel control member, and a collection pipe connected to the channel control member so as to communicate with the air discharge channel. Accordingly, the channel control member effectively prevents the outside air from reversely flowing into the air discharge channel. Further when sprayed into the aseptic chamber, the sterilant, gas or the like is discharged via the space between the aseptic chamber and the channel control member without the likelihood of flowing out through a space between the turntable and the control member, and is then collected by the collection pipe. This obviates the likelihood that the sterilant, gas or the like sprayed into the aseptic chamber will contaminate the work environment.
When the aseptic chamber is held at a positive pressure in its interior, with the interior of the collection pipe held at a negative pressure, the air can be prevented from reversely flowing into the air discharge channel more effectively.
When the seal means is a seal clearance provided between the turntable and the channel control member and communicating with the collection pipe, this simple means serves the function of a seal.
When the portion of the entire channel control member opposed to the turntable at least with the seal clearance formed therebetween is provided with a protective member, the protective member serves to minimize the possible trouble even if the turntable comes into contact with the channel control member.
If the air discharge channel is in the form of a labyrinth, the channel itself functions as a noncontact seal.
The seal means may alternatively be a seal member provided between the turntable and the channel control member.
The present invention provides another aseptic filling apparatus of the rotary type which comprises a closed aseptic chamber having a top wall and a circular opening in the top wall, and a turntable having an outer peripheral portion overlapping an edge portion of the top wall defining the opening for transporting containers and filling nozzles, an air discharge channel being provided between the opening-defining edge portion and the outer peripheral portion, the filling apparatus being characterized in that an annular channel control member is disposed around the turntable, a seal clearance being provided between the turntable and the channel control member, the channel control member being hermetically fixed to the aseptic chamber top wall so as to form a vent clearance between the top wall and the channel control member in communication with the air discharge channel and the seal clearance, a collection pipe communicating with the vent clearance.
Preferably, the vent clearance is greater than the seal clearance.
Preferably, the interior of the aseptic chamber is held at a positive pressure, and the interior of the collection pipe is held at a negative pressure.
Further preferably, the portion of the entire channel control member opposed to the turntable at least with the seal clearance formed therebetween is made from a material having at least one of the properties of lubricity, heat resistance and resistance to chemicals.
Further preferably, an upward annular ridge formed on an upper surface of the opening-defining edge portion of the top wall and a downward annular ridge formed beneath a lower surface of the turntable outer peripheral portion are positioned in the air discharge channel inwardly or outwardly of each other.